Mystery instability of 16f628a

[Davidmarks]

Thanks Joe. As I said in previous post the thing is working OK now. Didn't know about the need to change the inc file for the internal oscillator, but I have now done so and relieved to find it still works. The [ symbol was intended to signify the start of the code.. seem to remember someone telling me that I should do that when posting code. I now have yet another seemingly inexplicable problem. I am programming in circuit with PicKit 2 which has suddenly decided to stop the circuit working if I disconnect it. I have a seperate power supply which is powering the circuit so simply cannot understand why it should stop working when I remove the PicKit2 . It wasn't doing it earlier this week so I am at a loss to know what I have done ( nevertheless I'm pretty sure that I know who is to blame again!)
Cheers
David M

[Archangel]

Microchip sells demo boards at a reasonable price which simply plug into the pickit2. I like them for testing code snippets, easy quick push button changes and viola it is running again, no wires to fuss with. different boards for the 628 and similar vs 690 series. As for who is to blame . . . blame it on the curve, the learning curve, we ALL have lost it on that curve, be careful not to oversteer, so as not to spin out

[mackrackit]

I am programming in circuit with PicKit 2 which has suddenly decided to stop the circuit working if I disconnect it.

Sounds like a MCLR issue. Try _MCLRE_OFF
in your configs.

[Pimentel]

Put a 100nF capacitor near pins 5 and 14 (gnd and vcc) !
Its solve my mistery problems in the pass.

Good luck
Pimentel

[hardcore]

I had problem with 16f628a
After repeating to reprogram IC with the same code it start working as has to be.
Possible disadvantage of 16f628a is some bits of reprogrammed memory do not change their state during programming.
Hope it helps.
hardcore

[George]

Hi David,

I had exactly the same problem as you seem to be having with a project I'm currently working on, also with a PIC16F628a.

I found the answer to be _LVP_OFF

What would happen is it defaults to LVP on, each time it would get a signal on the LVP pin, the micro would reset, hope this helps